Yuasa Motorbike battery YTB9 12V 9.5Ah (AGM maintenance-free)

The Yuasa YTB9 is – just like the YTB4L – a special modern upgrade for classic motorbikes. It was developed to replace the traditional YB9-B (12N9-4B-1) lead-acid battery 1:1. With a capacity of 9 Ah (10h) or 9.5 Ah (20h) and compact dimensions, it brings the benefits of AGM technology to older vehicles originally designed for open acid batteries.

Highlights at a glance

• Plug & Play upgrade for YB9-B: It has exactly the same dimensions (135x75x139 mm) as the classic. It fits perfectly in the battery box of Vespa PX 200 E Lusso, Honda CB 125 T or older Yamaha models.
• 100% maintenance-free: Unlike the old YB9-B, water never needs to be topped up again. The battery is hermetically sealed thanks to VRLA technology.
• No acid hose: As the YTB9 is sealed, the vent hose required for the old battery is not needed. This protects the frame and exhaust from corrosion damage caused by acid droplets.
• AGM technology: The acid is bound in the fleece (Absorbent Glass Mat). This makes the battery leak-proof and much more vibration-resistant than the old wet battery.
• More power: Often offers better cold start values and maintains voltage longer, which is especially helpful for vehicles with a weak alternator or infrequent use.

The upgrade for Vespa PX & classics

The YTB9 is the perfect choice for anyone who wants to "modernise" their classic without changing the look or the battery box. It is particularly popular with riders of the Vespa PX (with electric starter, 12V), the Piaggio Hexagon, the Honda VT 250 or the Aprilia AF1, all of which came with the maintenance-intensive YB9-B as standard. With the YTB9, fiddling with acid packs and checking water levels is a thing of the past.
 

Features

FAQs about the Yuasa YTB9

What is the difference from the YB9-B?

The size is identical, the technology is the difference.

• YB9-B (Old): Open acid battery with 6 plugs, must be regularly topped up with distilled water, needs an overflow hose.
• YTB9 (New): Sealed AGM battery, completely maintenance-free, leak-proof, requires no hose.

What is the difference from the YT9B-BS?

Attention, risk of confusion due to similar names!

• YTB9 (Your battery): 135 x 75 x 139 mm (tall and narrow, for old bikes).
• YT9B-BS (Completely different): 150 x 70 x 105 mm (flat and long, for Yamaha XT660). The two batteries are mechanically not interchangeable. Pay attention to the order of the letters!

Can I install this battery lying down?

Since it is an AGM battery, it is theoretically leak-proof. However, the YTB9 is primarily designed as a replacement for the YB9-B, which was always fitted upright. The terminals are therefore often arranged to fit best when upright. Technically, there is nothing against a VRLA battery (provided it is activated and sealed by the manufacturer) being tilted, but with vintage vehicles, the upright position is usually preferred.

My scooter has an acid sensor, does it still work?

Some old Vespa or Piaggio models had a level sensor that was inserted into one of the plugs of the wet battery. As the YTB9 has no plugs (it is maintenance-free), you can no longer use this sensor. But that's not a problem: as the battery does not lose water, you no longer need a warning light for it. Just insulate the cable for the sensor well.